Seismological monitoring of the Comprehensive Nuclear-Test-Ban Treaty

Seismological monitoring is one of the four technologies used by the International Monitoring System to verify compliance with the Comprehensive Nuclear-Test-Ban Treaty. When fully operational, two seismic networks, one primary (50 stations) and one auxiliary (120 stations), will enable global detection and event characterisation of sources with equivalent magnitude as low as 4. The basic principles of seismological theory and practice applied to verification are summarised below, with particular emphasis on the new requirements imposed by the needs of the Treaty.